How to Replicate Horizon in Overdub Studio

A customer wrote in last week with a fair question. He noticed Horizon Engine had dropped in visibility on the dashboard, tried Overdub Studio, decided it didn't do what he needed, and asked point blank: are you about to discontinue Horizon?

The short answer is no. Horizon is still live and it stays live. But the question deserved more than a two-line reply, because there's a real workflow answer buried in it. Everything Horizon did, Overdub Studio now does through Manual Extension.

So I recorded a video showing the exact replication, start to finish. This post is the written version, with timestamps if you want to jump around.

Replicating Horizon in Overdub Studio (2 min)

I open Horizon, then rebuild its workflow in Overdub Studio: full lyrics, one changed section, and a Manual Extension primer window set in seconds.

Video chapters

• 0:00The customer question: is Horizon going away?
• 0:11Where Horizon lives now, plus the link inside Overdub Studio
• 0:27How Horizon works: a section tag plus start and end times
• 0:41Step 1: paste the full song lyrics (database or Genius)
• 1:01Change only the section you need, then lock
• 1:14Manual Extension: setting the primer window, the Horizon part
• 1:33Why Manual is not the default strategy
• 1:48Where to start and end a manual window
• 2:11What Auto Extension already does for you

The Short Answer

Horizon isn't going anywhere. You can still open it at changelyric.com/dashboard/v2-horizon. There's also a link to it at the top of Overdub Studio, so it's two clicks from wherever you already work.

What changed is the front door. When Overdub Studio shipped in September, it replaced both the old Overdub and Horizon as the default editor. One guided workspace beat three separate tools, so Studio became the thing we point new users at first.

Here's the honest part. A lot of people had a hard time wrapping their heads around how Horizon worked. Picking your own start and end times is a power-user move. That's why the Horizon-style controls sit lower in Studio's strategy list. They're all there. We just stopped putting them first.

How Horizon Worked

If you never used Horizon, here's the 30-second version. You gave it three things: the tag for the section you wanted, a start time, and an end time. Something like [Verse 1], 0:23 to 1:12.

The engine treated that window as its primer. It regenerated the vocal for your changed lyrics in place and left the rest of the track alone. That made Horizon the tool for small, surgical edits. We leaned on it exactly that way on a one-word Queen swap where V3 had struck out three times in a row.

There's a full tutorial on the Horizon page itself if you want the original walkthrough. The rest of this post is about getting the same behavior inside Studio.

The Overdub Studio Equivalent, Step by Step

Manual Extension in Overdub Studio is the same mechanism with a new address. Here's the whole path, matching the video.

Step 1: Paste the Full Song Lyrics

This is the one real difference between the tools. Horizon only needed the section you were changing. Studio wants the complete lyric sheet.

Pull lyrics from the built-in lyric database or grab them from Genius. In my experience Genius tags are the more reliable of the two. You could probably get away with a partial paste, but don't. Full lyrics, proper tags, every time.

Step 2: Change Only the Section You Care About

Edit only what you're changing. If that's one verse, change that one verse and leave everything else exactly as the original.

This is the same rule that runs through everything on ChangeLyric: the smaller the delta between original and new lyrics, the better the engine does. Change less when you have the choice.

Step 3: Lock and Check Your Section Times

Lock your sections and Studio moves you to the section view, where it has detected where each part of the song sits. Double-check the times on the section you're changing.

Detection is good but can land a little off. Your manual window is only as good as the map it's drawn on, so fix a misdetected boundary here before going further.

Step 4: Open Manual Extension and Set the Primer Window

Now the Horizon part. Select your target section, choose Manual Extension, and set the primer window times.

Target section:  [Verse 1]
Primer window:   45s to 180s

Start time, end time, in seconds. This is the exact same control Horizon exposed. Type 45 and 180, and the primer window becomes 45 seconds to 180 seconds. I use those numbers in the video on purpose, because that's the kind of input Horizon used to take.

Step 5: Aim the Window the Way Horizon Expected

Where you point the window matters more than the numbers. If you're replicating the first verse, start the window right where that verse begins. In the video that's around 0:23.

For the end, find the next occurrence of the same section and stop right before it. First verse, through the chorus, ending just before verse two comes back around.

That shape isn't arbitrary. It hands the engine your target section plus the section after it, which is the context it needs to repaint in place instead of drifting off the melody.

Horizon and Studio, Side by Side

A quick cheat sheet if you're moving between the two:

• Input: Horizon wanted one tagged section. Studio wants the full lyric sheet with tags.
• Targeting: Horizon used a tag plus start and end times. Studio uses the section picker plus the Manual Extension window.
• What gets changed: both repaint only your target section and leave the rest of the track alone.
• Takes: Horizon returned a couple of variants. Studio queues multiple strategies and you checkmark keepers onto a comp lane.
• One-word and one-line edits: that was Horizon's sweet spot. In Studio it's inpaint with the Single scramble setting.
• Downloads: Studio hands you a stem ZIP with the master, vocal buses, and instrumental, plus the comp lane file for your DAW.

If you're coming from Horizon, everything maps one to one. The only new habit is pasting the full lyric sheet instead of a single section.

When Manual Extension Is Worth It

My honest recommendation: most of you shouldn't use it.

That's not me talking the feature down. It's the same reason Manual sits low in the strategy list. Generative music extensions are hard to wrap your head around. You're handing the engine audio and asking it to continue and repaint at the same time. Plenty of experienced producers find that unintuitive at first, and that's fine.

Auto Extension already does the aiming for you. It takes your target section, includes the next section, and cuts right before the one after that. Verse, then chorus, stop before the next verse. That's exactly the window you'd build by hand in Step 5.

So reach for Manual when Auto's guess is wrong. Section detection off by a few seconds. A window you want tighter or longer than Auto picks. Or you simply already think in start and end times because Horizon trained you, and that's a good reason. It's who this post is for.

After the run, the flow is the same as any Studio job. Listen to the takes, checkmark the keepers, and comp them in your DAW from the comp lane download. The comping section of the launch post walks through that part.

What About Self-Hosting?

The same customer had a follow-up question: can you download Horizon and host it on your own servers, and what would it cost?

The answer is no. The pages you see in the dashboard are interfaces. The actual generation runs on GPU infrastructure we maintain, and we can't package that engine up and hand it over.

What I can tell you on the record: Horizon stays running for the foreseeable future. If that ever changes it won't be a quiet removal. Customers who rely on it will hear about it well ahead of time, with a migration path.

Bottom Line

Horizon is still live at its URL and linked at the top of Overdub Studio. If its workflow is how you think, Manual Extension gives you the same primer window control inside the newer editor, with take review and stem downloads in the same place.

And if you've never touched either tool, start with the getting started guide, then let Auto Extension do the aiming while you learn the rest.

You can run the whole workflow on the ChangeLyric dashboard right now, Horizon included.